Blind mice see the light after simple drug therapy

If it's beyond repair, you find something else to do its job. This could soon apply to rods and cones, the light-sensitive cells in our eyes that can wither with age, causing blindness. A drug has been found that coaxes neighbours of ailing cells to do their work for them.

But it only worked with ultraviolet light. Now, Kramer's team has found a different drug that does the same with visible light. Just 6 hours after they were injected, blind mice could learn to respond to light in the same way as sighted mice – although Kramer says he doesn't know whether they regained vision or just light sensitivity.

Selective effect

When the researchers studied the drug's impact on retinal cells in more detail, they realised it had had no effect on healthy cells. "That's what's particularly remarkable and hopeful about this," says Kramer. "It's possible that if you put this drug in a partially damaged eye it would restore vision to the damaged regions and leave the healthy areas unaffected – although we haven't done the experiments to test that."

Gene therapy and stem cell treatments are also being explored as ways to restore sight, but a drug would be simpler and any side effects should be reversible, says Kramer.

"The light responses that are generated could be very noisy and not useful – or even disturbing," he says. "Or perhaps the brain could learn to interpret the new information. But this needs to be demonstrated."

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